1. Field of the Invention
The invention relates to a buckle construction and in particular to an integrally molded plastic buckle for securing flexible strapping. More particularly, the invention relates to a buckle construction for securing non-metallic strapping about an object without piercing or indenting the strapping material.
2. Description of the Prior Art
Buckles of various constructions and arrangements have been used in the past and are being used today for securing together the ends of strapping material used to bind or secure an object. Metal strapping was used to a great extent in the past for securing together large objects requiring considerable tension on the strapping. Plastic strapping, however, has replaced the use of this metal strapping for many applications.
Various buckle constructions have been devised for securing the ends of flexible or plastic strapping which secure the strap ends by clamping or wedging the strapping between separate frame members to eliminate piercing or indenting the strap material. Examples of such buckle constructions are shown in U.S. Pat. Nos. 139,777, 151,191, 728,206, 2,914,827, 3,121,270 and 3,377,666.
Such buckles have not proven entirely satisfactory in that two separate members are required which makes installation thereof time consuming and more difficult than a single member buckle. Also, many of these prior constructions do not provide the desired gripping ability, and permit the strap to loosen and slip in the buckle. Likewise, many of these prior constructions are formed of metal which is both costly and difficult to produce.
Recent buckle constructions have been produced as relatively inexpensive integrally molded plastic members which eliminate many of the problems encountered with prior two-piece, metal buckle constructions. Examples of these plastic buckles are shown in U.S. Pat. Nos. 3,206,816, 3,271,831, 3,336,639 and 3,414,943.
Difficulties have been encountered with the type of buckle constructions as shown in U.S. Pat. No. 3,206,816 in that the rigid connection between one end of the pair of clamping fingers increases the difficulty of placing the fingers in the loops formed in the strap ends. Both fingers must be inserted within the strap loops before the buckle can be moved to folded position. Likewise, when used for high tension applications, tension on the fingers may cause twisting of the front finger ends with respect to the rigid connection therebetween causing slipping of the strap within the buckle and possible fracture of the finger at the junctions with the rigid rear cross member.
Buckle constructions of the type as shown in U.S. Pat. No. 3,414,943 have eliminated some of these prior buckle installation problems by providing the strap clamping fingers with separate flexible connecting hinge strips. These separate strips permit independent movement of the fingers during strap securement. Such constructions, however, have not proven entirely satisfactory in that upon tensioning of the strap, the fingers are pulled in a generally inwardly downwardly direction and any slight unequal force causes the unattached finger ends to turn. This turning causes an unequal force on the rear portion of the fingers resulting in fracture thereof, especialy when considerable tension is required and is applied by mechanical means. Also, the unattached ends of the fingers may contact each other and override causing slippage of the strap, and increasing the difficulties of using the same.
No buckle construction for flexible strapping of which I am aware has eliiminated these installation problems by providing a pair of independently movable fingers having a pair of fixed posts between the spaced end of the fingers, which posts absorb much of the tensioning forces and equally distributes the remaining forces on the fingers preventing twisting, turning and premature fracture of the fingers.